High intensity discharge (HID) lamps employ arc discharge tubes of glass or ceramic that operate at pressures much higher than atmospheric pressure. On rare occasions these arc tubes have been known to fail in a non-passive manner and deposit glass shards in a wide area about the lamp. Because of this problem such lamps have had to be operated within an enclosed fixture to offer protection and to provide containment of the shards in the event of a burst of the arc tube. Recently, so-called protected versions of these lamps have been made available. These protected lamps have used a shroud of glass or quartz to surround the arc tube and, in conjunction with a heavy-walled envelope, are capable of being operated in an open fixture. Shrouds for metal halide arc discharge lamps are disclosed in U.S. Pat. No. 4,499,396 issued Feb. 12, 1985 to Fohl et al.; U.S. Pat. No. 4,580,989 issued Apr. 8, 1986 to Fohl et al.; and U.S. Pat. No. 4,888,517 to Keeffe et al, issued Dec. 19, 1989. See also U.S. Pat. No. 4,281,274 issued Jul. 28, 1981 to Bechard et al. However, these lamps still have a relatively large body using a mogul base and are not suited for operation in downlight fixtures. The lamps used in downlighting applications are typically incandescent PAR and E17 lamps as well as T4/T6 bi-pin types. It would be advantageous if a low-wattage (e.g., <100 watts), medium screw base lamp with a shorter overall length than a PAR lamp or an E17 lamp could be provided.